Method of marking or inscribing a workpiece

Abstract

The present invention provides a method of and apparatus for marking or inscribing a workpiece ( 3 ) with high-energy radiation, more particularly with a laser beam ( 1 ), the workpiece ( 3 ) having a light-scattering surface ( 9 ) and the material of the workpiece ( 3 ) being transparent for the radiation wavelength, and a polymer matrix ( 7 ) being disposed on the workpiece ( 3 ) in such a way that the radiation passes through the workpiece ( 3 ) and its light-scattering surface ( 9 ) before impinging on the polymer matrix ( 7 ), characterized in that the light-scattering surface ( 9 ) of the workpiece ( 3 ) is wetted with a liquid or viscoelastic medium ( 11 ).

The invention claimed is: 
     
       1. A method of marking or inscribing a workpiece ( 3 )
 comprising the steps of
 providing high-energy radiation ( 1 ), 
 providing the workpiece ( 3 ) having a light-scattering surface ( 9 ) and made of a transparent material for the radiation wavelength, and having a polymer matrix ( 7 ) being disposing on the workpiece ( 3 ) in such a way that the radiation passes through the workpiece ( 3 ) and its light-scattering surface ( 9 ) before impinging on the polymer matrix ( 7 ), 
 wetting the light-scattering surface ( 9 ) of the workpiece ( 3 ) with a liquid or visco-elastic medium ( 11 ), and 
 
 wherein the radiation induces removal of material from the polymer matrix ( 7 ), and resultant products deposit on the workpiece ( 3 ) in the form of a marking or inscription, and 
 wherein the liquid or viscoelastic medium ( 11 ) is removed from the light-scattering surface ( 9 ) after the marking or inscribing. 
 
     
     
       2. The method according to  claim 1 , further providing the liquid or viscoelastic medium ( 11 ) with a refractive index similar to that of the material of the workpiece ( 3 ). 
     
     
       3. The method according to  claim 1 , wherein the liquid or viscoelastic medium ( 11 ) in the wavelength range of 600 nm-1500 nm exhibits no absorption or has a degree of absorption of less than 10%, and using radiation in the wavelength range of 600 nm to 1500 nm. 
     
     
       4. The method according to  claim 1 , wherein the light-scattering surface ( 9 ) is wetted with a 250 nm to 10 mm layer of the liquid or viscoelastic medium ( 11 ). 
     
     
       5. The method according to  claim 1 , wherein the material of the workpiece ( 3 ) is a glass substrate which in the wavelength range of 600 nm to 1500 nm exhibits no absorption or has a degree of absorption of less than 10%, and using radiation in the wavelength range of 600 nm to 1500 nm. 
     
     
       6. The method according to  claim 1 , wherein the polymer matrix ( 7 ) is disposed in contact with a surface ( 5 ) of the workpiece ( 3 ) which is opposite the light-scattering surface ( 9 ). 
     
     
       7. The method of  claim 1 , wherein the high-energy radiation originates from a laser beam.